Several problems seem to occur over and over, and I have prepared a
little list of things to look out for. While the items below might
not all be considered errors, I believe paying attention to them will
improve the clarity of astronomical papers. This is a form letter,
and many of the items may not apply to your manuscript. I welcome
suggestions for modifications or extensions of these guidelines.
1. Astronomical nomenclature has been a continuing problem. For
Journal publication, all objects mentioned must be unambiguously
identified. The "lifetime" of a Journal article can be decades, and
nicknames that are popular today may fall out of use in the future.
Newly-discovered objects must be assigned proper names for future
reference.
The specific requirements for Journal articles are:
a) All objects must be labeled by a "Class I" or "Class II" name.
(See information at http://cfa-www.harvard.edu/~willner/desig.html ).
Punctuation (e.g., space, equal sign, slash, dash or minus sign,
parentheses, and colon) within and between names must be used
correctly.
b) Pre-existing source names should not be changed, but if they are
non-standard or unfamiliar, a reference to the original source of the
designation should be given. New names may be assigned to
previously-known sources, e.g., for consistency or clarity or as part
of a compilation of data. If new names are created, cross-reference
to old names should be given.
c) Newly identified objects should be assigned Class I names, and the
exact form of these names must be made clear for future use.
d) All new names assigned (per b or c above) should follow IAU
guidelines.
For a few objects, incorrect names have been used in the literature
more often than the correct names. Authors should consult with me
about individual cases, but very often the solution will be a
footnote giving both the correct and incorrect names.
References to the guidelines and additional advice is available at
http://cfa-www.harvard.edu/~willner/desig.html
I strongly encourage authors who have questions about designations to
read that material.
2. Figures together with their captions should be as self-contained as
possible. The caption (or the figure itself) should describe the
symbols used, all lines and curves, and anything else directly related
to the figure.
The concept applies more weakly to tables, where it may be necessary to
explain in the text how tabulated quantities were derived. Even for
tables, though, careful use of column headings and table notes can
often simplify and thereby clarify the manuscript. In most cases, at
least the basic nature of each column should be apparent without
reference to the text.
Information given in figure captions or table notes should not be
repeated in the text. There is no need to enumerate table columns,
explain which symbols show what, or to describe what readers can
plainly see for themselves. The text should explain the scientific
implications of the figure or table.
3. The pronoun 'we' is no longer forbidden in scientific manuscripts,
but it can be distracting if used excessively. A good rule is to use
'we' only where there is an element of personal judgment or where the
syntax would otherwise be horribly convoluted. Changing sentences to
passive voice is one possibility, but a much better solution is to
rewrite the sentence with an added idea. For example, instead of "We
fit a blackbody to the data," write "A blackbody is a good fit to the
data," or even better, "A blackbody fits the data to within 10%."
The improved form adds the idea that the fit was a good one, and the
final form makes the result quantitative. Both improved forms make
the object of the "we-sentence" the subject of the new sentence.
Quite often a relevant idea to add can come from the very next
sentence in the manuscript.
4. Instead of "In Figure XX we show...," a much simpler construction
is "Figure XX shows...." The same applies where the noun is Section,
Table, or even the entire paper ("This paper presents...") and for
any verb.
5. Data are given "by (authors)," not "in (authors)." The latter
evokes a most unsavory image.
6. Please be careful about using 'order' versus 'degree'. 'Order' is a
general indication of complexity; it is proper to refer to the "order"
of a differential equation or, for example, "accurate to first order."
'Degree' always denotes a polynomial and is almost always better when
it applies because it specifies the functional form exactly. You can
often simplify your text by referring to a second degree polynomial as
a quadratic and a third degree polynomial as a cubic.
7. Prefatory phrases like 'Note that...', 'It is important to note
that...', 'It can be seen that...', 'It is clear that...', 'We find
that...', 'We see that...', and many others are usually best omitted.
In general, they tend to detract from rather than emphasize the
importance of what follows. If you want to emphasize, usually the best
thing is to use a stronger verb. Even adverbs like "very" can have a
dubious effect. (Cf. "...can have a _very_ dubious effect.) See also
item 3 for phrases involving 'we'.
8. Please don't use 'error' where you mean 'uncertainty' (or vice
versa, for that matter). Even though the word is often used loosely,
'error' is a synonym for 'mistake'. A statistical estimate of some
true value has an 'uncertainty'. ('Error bar' is acceptable; it is one
of the many anomalies of English usage.)
9. Explanation of color figures can be confusing. As guidelines,
"true color" means an image as it would be seen by human eyes.
"False color" once meant an image as it would be seen if our eyes
were sensitive to different wavelengths than they are (e.g., an
infrared JHK image), but the term has been so badly misused as to
have lost all meaning. Probably "composite color" is the best phrase
for such images, but the caption must explain what each color
represents. If color is used to indicate surface brightness -- a
practice that is seldom justified, given that a grey-scale image can
usually show the same information -- the result is a "coded
intensity" image. I'm not sure there is a good term for images where
color represents some unrelated quantity such as radial velocity;
again the caption must explain. (I welcome suggestions.)
10. All displayed equations should be numbered, even if the text does
not refer to them. Other papers that refer to yours may need to cite
specific equations.
11. Figures and Tables should be numbered in the order in which the
text refers to them.
12. Dates should be presented in the order year-month-day. Please
use a four-digit year number. The ISO standard (for tabular dates)
is to put a hyphen between year and month and between month and day,
but I don't insist on that.
13. The abstract should state the principal methods employed and
summarize the main results of the study. The abstract should be
written for non-specialists and should be as concise as possible
consistent with clarity. In particular, it should avoid detailed
explanations and qualifications. Where results may be subject to
doubt, that can be indicated by choice of verb (e.g. 'suggest') or
adverb (e.g. 'likely'). It is not necessary to list all of your minor
results if a specialist will expect their existence from the rest of
the abstract. The abstract is not the place to summarize previous
results except on the rare occasions when a brief summary of an
unfamiliar problem needs to be given. Nor is it the place to explain
the motivation for your work nor to "advertise" how new and wonderful
your work is. Mention of possible future work also does not belong in
the abstract. The abstract should not contain symbols except for the
most familiar ones. ('M' for mass is OK, but anything less familiar
than that is dubious.) Key results should be explained in words.